This application relates to a system for controlling the application of lead oxide paste to a grid to form a plate for a lead-acid storage battery.
Various systems for applying lead oxide paste to a grid to make a battery plate are known in the art, being described, for example, in Yanik U.S. Pat. No. 4,606,383, Lund U.S. Pat. No. 2,840,120, McDowall et al, U.S. Pat. No.4,307,758, Pankow et al U.S. Pat. No. 3,951,688 and Ching et al U.S. Pat. No. 4,050,482. Typically, in such prior-art systems, the amount of paste in the final product is regulated by measuring the weight or thickness of the plate off-line, using a scale or a caliper, and adjusting the width of a clearance gap through which the pasted grid passes. Such a procedure requires the continual attention of a human operator, and inevitably there is a considerable delay between the occurrence of a situation requiring attention and its subsequent detection and correction.
Moreover, implicit in this procedure is the notion that weight is a function of thickness, and vice versa. In fact, owing to the compressibility of the paste and the resulting variations in paste density, these quantities may vary independently. Thus a plate of constant thickness, while acceptable mechanically, may nevertheless exhibit variations in paste density over the area of the plate that are unacceptable from the standpoint of electrical performance. Conversely, an electrically acceptable plate of constant paste density may exhibit mechanically unacceptable variations in thickness. Finally, this procedure of the prior art does not address weight or thickness variations that may occur across the width of the pasted grid.